Re: Do children's heads stop growing at age three?

When does the head reach its full adult size?

When we talk about the growth of the “head” we need to recognize that there are two very different things going on. The neurocranium, the part that houses the brain, grows very rapidly in early development, and typically reaches adult size around the age of three. The visceral cranium, basically the face, grows at a much slower pace and may not reach final adult proportions until the age of 20. The reference you cited was really speaking of brain size, which while related to head size is not the same thing as head size. A young child’s head is almost all neurocranium. As the child ages, the face will get bigger and add to the overall size of the head.

I suspect that what you friend sees as a small head is more probably a result of inexperience in assessing human growth and variation than it is a problem with this little girl. Still, you could be right. There are several reasons why it is difficult to discuss the particulars of the child you are worried about.

First, there is no such thing as “normal” in biology. Instead, there is the average expression and the variation about that average. The very nature of “average” means that some individuals are above that value and some are below – but they are all normal in the sense that this variation is to be expected. A small head may not be pathological, it may just be on the small end of the expected variation.

More importantly, it is impossible, impractical and inappropriate to diagnose a health condition over the internet. If your friend has access to regular head care, the little girl should have had several visits to a pediatrician by now. If the little girl’s doctor (an expert in the field) is not concerned about her growth, then no one else should be. If the girl has not had regular medical checkups, bring her to a physician. That will address all your concerns and questions better than I can do here.